BUGFIX: modifier: respect GPU volume-mount device requests

[ArangoGutierrez]

The gated modifiers used to add support for GDS, Mofed, and CUDA Forward Comatibility only check the NVIDIA_VISIBLE_DEVICES envvar to determine whether GPUs are requested and modifications should be made. This means that use cases where volume mounts are used to request devices (e.g. when using the GPU Device Plugin) are not supported.

These changes make the extraction of devices for gated and graphics modifiers consistent with other methods.

Fixes: #1049

[Copilot]

Pull Request Overview

This PR privatizes the legacy VisibleDevicesFromEnvVar method and ensures all modifiers use the public VisibleDevices API to query requested devices.

• Swapped calls from VisibleDevicesFromEnvVar() to VisibleDevices() in each modifier
• Renamed and privatized VisibleDevicesFromEnvVar to visibleDevicesFromEnvVar, and introduced a new visibleEnvVars helper
• Updated the unit test to exercise the private visibleDevicesFromEnvVar method

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
internal/modifier/graphics.go	Replaced VisibleDevicesFromEnvVar with VisibleDevices
internal/modifier/gated.go	Replaced VisibleDevicesFromEnvVar with VisibleDevices
internal/modifier/csv.go	Replaced VisibleDevicesFromEnvVar with VisibleDevices
internal/modifier/cdi.go	Replaced VisibleDevicesFromEnvVar with VisibleDevices
internal/config/image/cuda_image_test.go	Switched test to call visibleDevicesFromEnvVar
internal/config/image/cuda_image.go	Privatized VisibleDevicesFromEnvVar, added visibleEnvVars, updated VisibleDevices

Comments suppressed due to low confidence (2)

internal/config/image/cuda_image.go:233

• The new helper visibleEnvVars isn’t directly covered by existing tests. Consider adding unit tests to verify its behavior across different environment variable combinations.

func (i CUDA) visibleEnvVars() []string {

internal/config/image/cuda_image_test.go:432

• This test now calls an unexported method; ensure the test file is in the same package (not *_test) so it can access visibleDevicesFromEnvVar, or consider testing via the public VisibleDevices method instead.

devices := image.visibleDevicesFromEnvVar()

[coveralls]

Pull Request Test Coverage Report for Build 15704089585

Details

• 39 of 45 (86.67%) changed or added relevant lines in 4 files are covered.
• 4 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.05%) to 33.678%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
internal/modifier/gated.go	0	1	0.0%
internal/modifier/graphics.go	6	11	54.55%

Files with Coverage Reduction	New Missed Lines	%
internal/runtime/logger.go	4	43.51%

Totals
Change from base Build 15683627970:	0.05%
Covered Lines:	4338
Relevant Lines:	12881

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💛 - Coveralls

[elezar]

I may have mentioned this in #1110, but we already process the mount devices from above, and although this MAY have the desired effect we may want to revisit how we handle CDI device requests and how we distinguish between these are "regular" requests.

My suggestion would be to:

1. Keep VisibleDevicesFromEnvVar public for now.
2. Update the other usages as per this PR.
3. Handle CDI devices in a follow up.

[elezar]

Please update the commit messages / PR heading and description to better indicate intent. We are making this change to FIX A BUG. That is not clear from the commit messages and as such this will be missed in our release notes.

[elezar]

Please also add unit tests to capture the new behaviour in the affected code. (ideally first failing with the existing implementation).

This PR is not a blocker for the v1.18.0-rc.1 release.